Production of acetic acid with high conversion rate

Abstract

A process for producing acetic acid comprising the steps of reacting carbon monoxide and at least one of methanol and a methanol derivative in a first reactor under conditions effective to produce a crude acetic acid product; separating the crude acetic acid product into at least one derivative stream, at least one of the at least one derivative stream comprising residual carbon monoxide; and reacting at least a portion of the residual carbon monoxide with at least one of methanol and a methanol derivative over a metal catalyst in a second reactor to produce additional acetic acid.

1. A process for producing acetic acid, comprising
 reacting carbon monoxide and at least one of methanol and a methanol derivative in a first reactor under conditions effective to produce a crude acetic acid product; 
 separating, in a separation zone, the crude acetic acid product into at least one derivative stream, at least one of the at least one derivative stream comprising residual carbon monoxide; and 
 reacting at least a portion of the residual carbon monoxide with at least one of methanol and a methanol derivative over a metal catalyst in a second reactor to produce additional acetic acid. 
 
     
     
       2. The process of  claim 1 , wherein a product stream exiting the second reactor comprises less than 40 mol % carbon monoxide. 
     
     
       3. The process of  claim 1 , wherein the overall conversion of carbon monoxide is greater than 90%. 
     
     
       4. The process of  claim 1 , wherein the at least one derivative stream comprising residual carbon monoxide, comprises:
 from 10 mol % to 95 mol % carbon monoxide; and 
 from 5 mol % to 90 mol % at least one of methanol and a methanol derivative. 
 
     
     
       5. The process of  claim 1 , wherein the metal catalyst comprises a solid catalyst. 
     
     
       6. The process of  claim 5 , wherein the second reactor comprises a fixed bed reactor and the fixed bed reactor comprises the solid catalyst disposed in a catalyst bed. 
     
     
       7. The process of  claim 5 , wherein the second reactor comprises a trickle bed reactor and the trickle bed reactor comprises the solid catalyst disposed in a catalyst bed. 
     
     
       8. The process of  claim 1 , wherein the metal catalyst comprises a liquid catalyst. 
     
     
       9. The process of  claim 1 , wherein, in the second reactor, the at least one of methanol and a methanol derivative are liquids and the metal catalyst is a solid. 
     
     
       10. The process of  claim 1 , wherein, in the second reactor, the at least one of methanol and a methanol derivative, and the metal catalyst are liquids. 
     
     
       11. The process of  claim 10 , wherein the metal catalyst is a homogeneous liquid. 
     
     
       12. The process of  claim 1 , wherein, in the second reactor, the residual carbon monoxide and the at least one of methanol and a methanol derivative are vapors and the metal catalyst is a solid. 
     
     
       13. The process of  claim 1 , wherein, in the second reactor, the residual carbon monoxide and the at least one of methanol and a methanol derivative are vapors and the metal catalyst is a liquid. 
     
     
       14. The process of  claim 1 , wherein the reaction temperature in the second reactor ranges from 150° C. to 350° C. 
     
     
       15. The process of  claim 1 , wherein the reaction pressure in the second reactor ranges from 0.1 MPa to 10 MPa. 
     
     
       16. The process of  claim 1 , wherein the metal catalyst is a solid and comprises at least one metal selected from the group consisting of rhodium, iridium, ruthenium, nickel, and cobalt. 
     
     
       17. The process of  claim 1 , wherein the at least one of methanol and a methanol derivative, in the second reactor is provided by a supplemental feed stream or another of the derivative streams. 
     
     
       18. The process of  claim 1 , wherein the at least one of methanol and a methanol derivative is methyl acetate. 
     
     
       19. The process of  claim 1 , wherein the at least one of methanol and a methanol derivative is dimethyl ether. 
     
     
       20. The process of  claim 1 , wherein the separating comprises:
 flashing the crude acetic acid product into a first vapor stream comprising acetic acid and residual carbon monoxide and a first liquid residue stream comprising catalyst which is recycled to the first reactor; and 
 separating the flashed vapor stream into a second vapor stream comprising carbon monoxide, a purified acetic acid product, and a second liquid residue stream. 
 
     
     
       21. The process of  claim 20 , wherein the separating comprises:
 decanting the second vapor stream to form a third vapor stream comprising residual carbon monoxide and a third liquid residue stream comprising methyl iodide, methyl acetate, acetaldehyde; and 
 scrubbing the third vapor stream to form a fourth vapor stream comprising residual carbon monoxide and a fourth liquid residue comprising methyl iodide.